The thin glomerular basement membrane in children with haematuria.

To determine the specificity and significance of widespread attenuation of the glomerular basement membrane on electron microscopy, 240 renal biopsies from 218 children were studied retrospectively. Twenty-three patients showed diffuse attenuation and three of them are cases of hereditary nephritis. The other 20 patients are characterized by persistent microscopic haematuria, absence of proteinuria, normal blood pressure and renal function, and minimal glomerular changes. In 10 of these 20 children, microscopic haematuria was also present in the family. We conclude that widespread attenuation of the glomerular basement membrane is a characteristic of benign familial and non-familial haematuria. The thin glomerular basement membrane may be responsible for the haematuria and may result from incomplete glomerular maturation.